[SPARK-22830] [Improvements] Requested changes addressed

examples/src/main/scala/org/apache/spark/examples/BroadcastTest.scala

@@ -42,7 +42,7 @@ object BroadcastTest {
     val arr1 = (0 until num).toArray
 
     for (i <- 0 until 3) {
-      println(s"Iteration ${i}")
+      println(s"Iteration $i")
       println("===========")
       val startTime = System.nanoTime
       val barr1 = sc.broadcast(arr1)

examples/src/main/scala/org/apache/spark/examples/DFSReadWriteTest.scala

@@ -95,22 +95,22 @@ object DFSReadWriteTest {
   def main(args: Array[String]): Unit = {
     parseArgs(args)
 
-    println(s"Performing local word count")
+    println("Performing local word count")
     val fileContents = readFile(localFilePath.toString())
     val localWordCount = runLocalWordCount(fileContents)
 
-    println(s"Creating SparkSession")
+    println("Creating SparkSession")
     val spark = SparkSession
       .builder
       .appName("DFS Read Write Test")
       .getOrCreate()
 
-    println(s"Writing local file to DFS")
+    println("Writing local file to DFS")
     val dfsFilename = s"${dfsDirPath}/dfs_read_write_test"
     val fileRDD = spark.sparkContext.parallelize(fileContents)
     fileRDD.saveAsTextFile(dfsFilename)
 
-    println(s"Reading file from DFS and running Word Count")
+    println("Reading file from DFS and running Word Count")
     val readFileRDD = spark.sparkContext.textFile(dfsFilename)
 
     val dfsWordCount = readFileRDD
@@ -125,11 +125,11 @@ object DFSReadWriteTest {
     spark.stop()
 
     if (localWordCount == dfsWordCount) {
-      println(s"Success! Local Word Count ($localWordCount) 
-                and DFS Word Count ($dfsWordCount) agree.")
+      println(s"Success! Local Word Count $localWordCount and " +
+        s"DFS Word Count $dfsWordCount agree.")
     } else {
-      println(s"Failure! Local Word Count ($localWordCount) 
-                and DFS Word Count ($dfsWordCount) disagree.")
+      println(s"Failure! Local Word Count $localWordCount " +
+        s"and DFS Word Count $dfsWordCount disagree.")
     }
 
   }

examples/src/main/scala/org/apache/spark/examples/DriverSubmissionTest.scala

@@ -29,18 +29,18 @@ import org.apache.spark.util.Utils
 object DriverSubmissionTest {
   def main(args: Array[String]) {
     if (args.length < 1) {
-      println(s"Usage: DriverSubmissionTest <seconds-to-sleep>")
+      println("Usage: DriverSubmissionTest <seconds-to-sleep>")
       System.exit(0)
     }
     val numSecondsToSleep = args(0).toInt
 
     val env = System.getenv()
     val properties = Utils.getSystemProperties
 
-    println(s"Environment variables containing SPARK_TEST:")
+    println("Environment variables containing SPARK_TEST:")
     env.asScala.filter { case (k, _) => k.contains("SPARK_TEST")}.foreach(println)
 
-    println(s"System properties containing spark.test:")
+    println("System properties containing spark.test:")
     properties.filter { case (k, _) => k.toString.contains("spark.test") }.foreach(println)
 
     for (i <- 1 until numSecondsToSleep) {

examples/src/main/scala/org/apache/spark/examples/HdfsTest.scala

@@ -26,7 +26,7 @@ object HdfsTest {
   /** Usage: HdfsTest [file] */
   def main(args: Array[String]) {
     if (args.length < 1) {
-      System.err.println(s"Usage: HdfsTest <file>")
+      System.err.println("Usage: HdfsTest <file>")
       System.exit(1)
     }
     val spark = SparkSession
@@ -39,7 +39,7 @@ object HdfsTest {
       val start = System.currentTimeMillis()
       for (x <- mapped) { x + 2 }
       val end = System.currentTimeMillis()
-      println(s"Iteration ${iter} took ${(end-start)} ${ms}")
+      println(s"Iteration ${iter} took ${(end-start)} ms")
     }
     spark.stop()
   }

examples/src/main/scala/org/apache/spark/examples/LocalALS.scala

@@ -110,7 +110,7 @@ object LocalALS {
         F = f.toInt
         ITERATIONS = iters.toInt
       case _ =>
-        System.err.println(s"Usage: LocalALS <M> <U> <F> <iters>")
+        System.err.println("Usage: LocalALS <M> <U> <F> <iters>")
         System.exit(1)
     }
 

examples/src/main/scala/org/apache/spark/examples/LocalFileLR.scala

@@ -58,10 +58,10 @@ object LocalFileLR {
 
     // Initialize w to a random value
     val w = DenseVector.fill(D) {2 * rand.nextDouble - 1}
-    println(s"Initial w: ${w}")
+    println(s"Initial w: $w")
 
     for (i <- 1 to ITERATIONS) {
-      println(s"On iteration ${i}")
+      println(s"On iteration $i")
       val gradient = DenseVector.zeros[Double](D)
       for (p <- points) {
         val scale = (1 / (1 + math.exp(-p.y * (w.dot(p.x)))) - 1) * p.y
@@ -71,7 +71,7 @@ object LocalFileLR {
     }
 
     fileSrc.close()
-    println(s"Final w: ${w}")
+    println(s"Final w: $w")
   }
 }
 // scalastyle:on println

examples/src/main/scala/org/apache/spark/examples/LocalKMeans.scala

@@ -88,7 +88,7 @@ object LocalKMeans {
       kPoints.put(i, iter.next())
     }
 
-    println(s"Initial centers: ${kPoints}")
+    println(s"Initial centers: $kPoints")
 
     while(tempDist > convergeDist) {
       val closest = data.map (p => (closestPoint(p, kPoints), (p, 1)))
@@ -114,7 +114,7 @@ object LocalKMeans {
       }
     }
 
-    println(s"Final centers: ${kPoints}")
+    println(s"Final centers: $kPoints")
   }
 }
 // scalastyle:on println

examples/src/main/scala/org/apache/spark/examples/LocalLR.scala

@@ -61,10 +61,10 @@ object LocalLR {
     val data = generateData
     // Initialize w to a random value
     val w = DenseVector.fill(D) {2 * rand.nextDouble - 1}
-    println(s"Initial w: ${w}")
+    println(s"Initial w: $w")
 
     for (i <- 1 to ITERATIONS) {
-      println(s"On iteration ${i}")
+      println(s"On iteration $i")
       val gradient = DenseVector.zeros[Double](D)
       for (p <- data) {
         val scale = (1 / (1 + math.exp(-p.y * (w.dot(p.x)))) - 1) * p.y
@@ -73,7 +73,7 @@ object LocalLR {
       w -= gradient
     }
 
-    println(s"Final w: ${w}")
+    println(s"Final w: $w")
   }
 }
 // scalastyle:on println

examples/src/main/scala/org/apache/spark/examples/SparkHdfsLR.scala

@@ -60,7 +60,7 @@ object SparkHdfsLR {
   def main(args: Array[String]) {
 
     if (args.length < 2) {
-      System.err.println(s"Usage: SparkHdfsLR <file> <iters>")
+      System.err.println("Usage: SparkHdfsLR <file> <iters>")
       System.exit(1)
     }
 
@@ -79,17 +79,17 @@ object SparkHdfsLR {
 
     // Initialize w to a random value
     val w = DenseVector.fill(D) {2 * rand.nextDouble - 1}
-    println(s"Initial w: ${w}")
+    println(s"Initial w: $w")
 
     for (i <- 1 to ITERATIONS) {
-      println(s"On iteration ${i}")
+      println(s"On iteration $i")
       val gradient = points.map { p =>
         p.x * (1 / (1 + exp(-p.y * (w.dot(p.x)))) - 1) * p.y
       }.reduce(_ + _)
       w -= gradient
     }
 
-    println(s"Final w: ${w}")
+    println(s"Final w: $w")
     spark.stop()
   }
 }

examples/src/main/scala/org/apache/spark/examples/SparkKMeans.scala

@@ -60,7 +60,7 @@ object SparkKMeans {
   def main(args: Array[String]) {
 
     if (args.length < 3) {
-      System.err.println(s"Usage: SparkKMeans <file> <k> <convergeDist>")
+      System.err.println("Usage: SparkKMeans <file> <k> <convergeDist>")
       System.exit(1)
     }
 
@@ -95,10 +95,10 @@ object SparkKMeans {
       for (newP <- newPoints) {
         kPoints(newP._1) = newP._2
       }
-      println(s"Finished iteration (delta = ${tempDist})")
+      println(s"Finished iteration (delta = $tempDist)")
     }
 
-    println(s"Final centers:")
+    println("Final centers:")
     kPoints.foreach(println)
     spark.stop()
   }

examples/src/main/scala/org/apache/spark/examples/SparkLR.scala

@@ -73,17 +73,17 @@ object SparkLR {
 
     // Initialize w to a random value
     val w = DenseVector.fill(D) {2 * rand.nextDouble - 1}
-    println(s"Initial w: ${w}")
+    println(s"Initial w: $w")
 
     for (i <- 1 to ITERATIONS) {
-      println(s"On iteration ${i}")
+      println(s"On iteration $i")
       val gradient = points.map { p =>
         p.x * (1 / (1 + exp(-p.y * (w.dot(p.x)))) - 1) * p.y
       }.reduce(_ + _)
       w -= gradient
     }
 
-    println(s"Final w: ${w}")
+    println(s"Final w: $w")
 
     spark.stop()
   }

examples/src/main/scala/org/apache/spark/examples/SparkPageRank.scala

@@ -49,7 +49,7 @@ object SparkPageRank {
 
   def main(args: Array[String]) {
     if (args.length < 1) {
-      System.err.println(s"Usage: SparkPageRank <file> <iter>")
+      System.err.println("Usage: SparkPageRank <file> <iter>")
       System.exit(1)
     }
 

examples/src/main/scala/org/apache/spark/examples/graphx/Analytics.scala

@@ -51,7 +51,7 @@ object Analytics extends Logging {
     val optionsList = args.drop(2).map { arg =>
       arg.dropWhile(_ == '-').split('=') match {
         case Array(opt, v) => (opt -> v)
-        case _ => throw new IllegalArgumentException(s"Invalid argument: ${arg}")
+        case _ => throw new IllegalArgumentException(s"Invalid argument: $arg")
       }
     }
     val options = mutable.Map(optionsList: _*)
@@ -77,14 +77,14 @@ object Analytics extends Logging {
         val numIterOpt = options.remove("numIter").map(_.toInt)
 
         options.foreach {
-          case (opt, _) => throw new IllegalArgumentException(s"Invalid option: ${opt}")
+          case (opt, _) => throw new IllegalArgumentException(s"Invalid option: $opt")
         }
 
         println("======================================")
         println("|             PageRank               |")
         println("======================================")
 
-        val sc = new SparkContext(conf.setAppName(s"PageRank(${fname})"))
+        val sc = new SparkContext(conf.setAppName(s"PageRank($fname)"))
 
         val unpartitionedGraph = GraphLoader.edgeListFile(sc, fname,
           numEdgePartitions = numEPart,
@@ -103,22 +103,22 @@ object Analytics extends Logging {
         println(s"GRAPHX: Total rank: ${pr.map(_._2).reduce(_ + _)}")
 
         if (!outFname.isEmpty) {
-          logWarning(s"Saving pageranks of pages to ${outFname}")
+          logWarning(s"Saving pageranks of pages to $outFname")
           pr.map { case (id, r) => id + "\t" + r }.saveAsTextFile(outFname)
         }
 
         sc.stop()
 
       case "cc" =>
         options.foreach {
-          case (opt, _) => throw new IllegalArgumentException(s"Invalid option: ${opt}")
+          case (opt, _) => throw new IllegalArgumentException(s"Invalid option: $opt")
         }
 
         println("======================================")
         println("|      Connected Components          |")
         println("======================================")
 
-        val sc = new SparkContext(conf.setAppName(s"ConnectedComponents(${fname})"))
+        val sc = new SparkContext(conf.setAppName(s"ConnectedComponents($fname)"))
         val unpartitionedGraph = GraphLoader.edgeListFile(sc, fname,
           numEdgePartitions = numEPart,
           edgeStorageLevel = edgeStorageLevel,
@@ -131,14 +131,14 @@ object Analytics extends Logging {
 
       case "triangles" =>
         options.foreach {
-          case (opt, _) => throw new IllegalArgumentException(s"Invalid option: ${opt}")
+          case (opt, _) => throw new IllegalArgumentException(s"Invalid option: $opt")
         }
 
         println("======================================")
         println("|      Triangle Count                |")
         println("======================================")
 
-        val sc = new SparkContext(conf.setAppName(s"TriangleCount(${fname})"))
+        val sc = new SparkContext(conf.setAppName(s"TriangleCount($fname)"))
         val graph = GraphLoader.edgeListFile(sc, fname,
           canonicalOrientation = true,
           numEdgePartitions = numEPart,